The pristine Platte river picks up microbial genes for antibiotic resistance as it flows past human settlements. Image: Philip Nealey/Getty

In the Rocky Mountains, the South Platte River system flows east through the Coloradan plateau that has plenty cattle ranches, sheep pastures, dairy farms, and water treatment plants. A new survey shows how human activities have affected the concentrations of antibiotic-resistant genes in the watershed.

According to a new study, more than 40% of tuberculosis infections that are resistant to front-line antibiotic treatments have also become resistant to some common backup drugs. Efforts to control tuberculosis are being hindered by the emergence of multi drug-resistant (MDR) strains, making it harder to combat.